Method for laser cutting of unfinished metal sheets and laser cutting machine for carrying out the method

Abstract

The invention relates to a method for laser-cutting sheet steel ( 1 ), wherein a sheet steel ( 1 ) is gradually inserted in a defined position into the cutting area ( 2 ) of a laser cutter in a direction of advance V in order to machine it. The sheet steel ( 1 ) is machined by laser cutting in a machinable area corresponding to the length of the cutting area ( 2 ), in the entire machinable area or only in a section thereof. The machined part ( 8 ) and the non-machined part ( 8 ) of the sheet steel may also only overlap in some sections ( 10 ). An automatic discharge device is also provided. The manufactured parts and the remaining grid are likewise cut from the sheet steel ( 1 ) by laser cutting. The method can be repeated in several machining steps until the sheet steel ( 1 ) is completely machined, the results of the preceding machining step being taken into consideration for the subsequent machining step. The invention allows to optimally utilize the sheet steel ( 1 ) even when using smaller laser cutters.

The invention claimed is: 
     
       1. A method for laser cutting of an unfinished metal sheet using a laser cutting machine, wherein the laser cutting machine has a laser cutting head that can be moved in a horizontal plane, and wherein the unfinished metal sheet is pushed into a cutting region of the laser cutting machine in an advance direction, piece by piece, for processing, wherein in a first step
 the unfinished metal sheet is processed in an entire region or only in a part of the region, by means of laser cutting, 
 finished parts and a residual lattice produced by means of laser cutting are also separated from the unfinished metal sheet by means of laser cutting, 
 the parts produced by means of laser cutting, together with the residual lattice, are subsequently removed from the cutting region of the laser cutting machine by means of an automatic removal device, and wherein the method can be repeated in the same manner in one or more processing steps, after removal of the finished parts with the residual lattice from the cutting region of the laser cutting machine, until the unfinished metal sheet has been completely used up, wherein the results of the preceding processing step are also taken into consideration in the case of each repeating processing step, 
 
       wherein the material utilization of the part of the unfinished metal sheet that is processed in the at least one repeated processing step takes place in such a manner that a parting line that runs at least partially at a right angle to the advance direction is cut at the front edge of a remaining non-processed part of the unfinished metal sheet, which parting line has no parts that project beyond it in the advance direction, and 
       an overlap region exists between the processed part of the unfinished metal sheet and the non-processed part of the unfinished metal sheet, wherein the overlap region can extend in a direction parallel and/or crosswise to the advance direction. 
     
     
       2. The method according to  claim 1 , wherein the method is repeated in at least one repeated processing step; and
 wherein the unfinished metal sheet and the part of the unfinished metal sheet that is processed are processed in such a manner that material utilization of the unfinished metal sheet is optimal. 
 
     
     
       3. The method according to  claim 1 , wherein after the production of parts via laser cutting and after separation of the processed part of the unfinished metal sheet from the non-processed part of the unfinished metal sheet
 a cutting table on which the finished parts and the residual lattice lie is lowered, in order to separate the processed part of the unfinished metal sheet from the non-processed part of the unfinished metal sheet, 
 a removal fork is moved into the cutting table and under the finished parts and the residual lattice that are lying on the cutting table, 
 the cutting table, on which the finished parts and the residual lattice are lying is lowered, thereby causing the finished parts and the residual lattice to come to rest on the removal fork, and 
 the removal fork together with the finished parts and the residual lattice now lying on the removal fork are moved out of the cutting region of the laser cutting machine by means of the automatic removal device, in a removal direction. 
 
     
     
       4. The method according to  claim 1 , wherein the removal of the finished parts and of the residual lattice takes place in a horizontal removal direction that is disposed at a right angle to the advance direction. 
     
     
       5. A laser cutting machine comprising:
 a cutting table movable in height; 
 a laser cutting head movable in any direction in a horizontal plane above the cutting table, in a cutting region; 
 a sheet metal advancing device for advancing an unfinished metal sheet in an advance direction, from a support table into a cutting region of the laser cutting machine, as well as for positioning the unfinished metal sheet in the cutting region of the laser cutting machine; 
 an automatic removal device comprising an unloading fork movable into and out of the cutting table; and 
 a control device for controlling laser processing processes of the laser cutting machine, as well as for controlling loading and removal processes as a function of the laser processing processes; 
 wherein the cutting table can be moved from a working height into a first plane lying underneath the working height; and 
 wherein the unloading fork can at the working height or at a height of the first plane move into and out of the cutting table to receive parts from the cutting table if the cutting table is lowered beneath the unloading fork. 
 
     
     
       6. The laser cutting machine according to  claim 5 , wherein the control device automatically performs a selection as to whether a transfer is carried out at the working height or at the height of the first plane as a function of a presence of an overlap region between a processed and a non-processed part of an unfinished metal sheet processed by the laser cutting machine. 
     
     
       7. The laser cutting machine according to  claim 5 , wherein the unloading fork can be moved in and out of the cutting table in a removal direction disposed at a right angle to the advance direction.